Overload is a Mage's first multi-target skill. It zaps the first target for 175% Magic DPS and then arcs to up to two more targets (no more than 5 yards away) causing 30% less damage each time. It has a 1.5 seconds cast time and can target both players and creatures.
Can be learned from a Scroll of Overload. One is given to you during the quest  Advanced Magic. (Should you somehow manage to lose it, you can buy one from a Combat Trainer for 25 silver.)
Talents that amplify Overload:
The damage of your Overload is increased by 20/40% Spell DPS and increases the maximum number of targets to 4/5
Your Overload applies Static Discharge for 12 seconds. Static Discharge slows the target by 15/30% and increases your offensive spell critical strike chance on the target by 4/8%